Marine steam-turbine.



1. F FME T TEN; MARINE SIEAM- TURBINE. APPLICATION HLED SEPT. 9. 1915.

Patented Apr. 15,1919.

630M itd z,

A TTORNEYJ,

' excess 7 or reaction blades.-

this type of turbine JOHN F. inn'rrnmonPHILADELP IA, rnnnsvnynifin,.Assmnon'ro 'rnn ILLIAM cam]? 85501 15 snxr a-n'njemn BUILDIN sYLvAnre.

o'o'MrANY, a conronn'rion or PENN- MARINE instream.

To all whom it may concern; r i

Be it known that 1, JOHN F. Merrnn, a citizen of the United States,resldmgat Philadelphia, in the county of Philadelphia nd State ofPennsy1vania,have invented certain new and useful .Improvements inMarine Steam-Turbines, of which the following is a full, clear, andexact specification.

This invention relates to turbines for driving a propeller shaft, and,

has for its-object to increase the. overall efliciency as compared w thconstructions previously used.- The invention has 'pan ticular referenceto turbines compose'dpf,

several wheel or c0mp011ndjvel0cityi stages followed by a solid headeddrumjcarrymg' a'number of single rows ofeither impulse the wheel orcompound velocity stages .to the least possible number, 4

many blades as possible onrthe drum bee cause the drum is "the moreetficient pa-rt of the 'turbine. In marine turbine installations, wherethe propeller" isdife cftlyhcoupled to the turbine shaft, it has-been;customary to cause the pressure ontheheadof the drum to be aboutiequal;to or slightly in of the propeller thrust, in order" to save wear onthe thrust blocksi In some instances, a part of'lthis thrust hasbeenpro:

duced by the reactionbladingon the drum,

but where impulse blading is"used the entire thrust opposing thepropeller has been exerted by the drum. As the diameter of the drumstages, whether of the reaction or of the impulse type, i determined bythe blade speed, the steam volume, etc, it has beenthe common practiceto carry the expansion of the steam in the wheel stages before admittingit to the drum stages farther than is desired for the best overalleconomy, since the drum stages are alway of better elliciency than thewheel stages. One reason for doing this has been in order tosecure therequisite low steam pressure,onthe head of the drum so as not to producea backward thrust too much in excess of the forward propeller thrust.

According to the present invention, a marine steam turbine is providedin which the relatively inefficient wheel stages are re- 'tained at orabout equal to the forward pro marine steam 1 a In he specificel bo imefr e The best i efficiency of depends upon reducing f and carrying as, pp

total, rearward pressure jexertedbythe main drai 'by the necessityadvantages ofthis construction, that. of increased overalleconomy,jarethat i tice; but is only subjected to thesamerean wardpressure as thatapplicd-zto the auxiltotal steam pressure on "the.

.the first stage and will run cooler.

, and a rearward bearingnot shown,-in the Specification a LettersPatent. Patented Apr, 15, 191 9., Application filed September-9,1915.Serial No. 49,661." 5

higher than has heretofore been employed, 'whlle at thesame timeenabling the backward thrust, onthe drum head to be main p'eller thrust.Thereby, a large number of relatively inefiicient wheel stages can berep'lacedby "relatively 'efiicifent drum stages workmg'at thesamezpressure, s0 that the ov ra efficiency, oflthe plant is very much.1ncreas --fv '65 tion herein shown, one of the forward wheels;preferably the initial one, is,pro

'yided with a smalldrum, oneside' of. said drum being subjected to steampressure led from one, oftheelower stages, for example,

from 1 drym'staganndthe other side i of the, drum being a subjected tothe; steam a pressureion the rear*of the first wheel. ,jfThe v inopposition *to the propeller thrust 15 thus reduced, so that the numberof a drum stage iwhiehcan beemployedis not liinited 1] ofeoordinatinggthje drum 1 pressure to the propellerthrust; Further" theforward gland ofi'the turbineisnot sub- 1 jected to the initial'high'steam pressure "in the-first 'wheel stage, as isthe usual prac iarydrum. The gland is thus simpler: in constructiomand easier to keep inorder. Also,. the forward bearing is; farther reg moved from the. hightemperature steam in The head of the turbine casing is also subjected toless total pressure, and consequently has less tendency to deflection.

In the accompanying drawing, .1 represents a turbine caslng in which apropeller shaft" 2. i ournaled in forwardbearing 3,

usual manner. lrepresents a propeller'carried by shaft 2. 5 representsthe forwardgland, which is ordinarily subjected -to the same pressure asthat admitted to theJfi-rst stage, ,Mounted on the shaft 2 'are' one ormore high'pressure wheels 6, and rearwardly 105 thereOf is'a drum ,7having forwardhead 8.

other than The wheels 6 have passages through them to equalize thepressure on the oppositefaces ofztheir webs and 9 are diaphragmscarryingnozzles l0iofany desired construction, and separating'theseveral wheel stages. The forward nozzles 10 are supplied with highpressure steam by a belt 11. The sev eral wheel stages are provided withfixed and moving blades of any usual construction, but preferably theblades are of the impulsetype. The drum 7 is also provided movingblades, which may be eitherof the impulse or of the reaction type, orpartly of both.

Mounted on the forward side of the first wheel 6 is a ring 13, whichcooperates with a; concentric ring 14 carried by the casing to form asteam tight joint. Ordinary gland packin'g'rings may be used for thispurpose. The chamber 16 therebyformed is connected by pipe 17 toa'chamber 18 formed in the casing of the drum stages,

and at such a point therein as will provide I .8 tending j peller willbe equal tothe total effective area pressure suflicient to reduce thetotal rearward pressure on the main drum head 8 to the desired amount. V

, The rearward pressure produced'by' drum to oppose the thrust of theproof the drum'8 multiplied by the steam pressure on the forward sidethereof, which will considerably exceedthe' forward thrust of thepropeller. At the same time, there will V 1 steam pressurefin the firtiplied by the elfective hey a forward thrust on that portion of thefirst wheel 6 whichis included within the ring-'13, this thrust beingproduced by the st wheel stage mularea of this auxiliary drum. Bypartially or wholly balancing thisffo rce by steam through the pipe .17from one of the lower drum stages. it

will be seen that the total pressure'of drum 7 Sis reduced so as tobalance; the propeller prevents the initial high pressure steamthrust tothe desired extent. The'combination of the auxiliary forward drum withthe'main drum renders it possible to bring the latter forward into thehigher pressure stages of the'turbine toreplace wheel stages, and alsoto increase the diameter of the drum, without necessitating too greatarearward drum thrust. The elimination of wheel stages effects a largesaving in the cost of building a turbine, besides increasing the overallefliciency. As will be seen from the drawing, the auxiliary drum chambercommunicates with the forward gland, and

from acting thereon. This saves wear and special construction toresisthigh pressure, and also. maintains the forward bearing at alowverrunning temperature. I f

It will be obvious that the auxiliary forward drum need not be carriedby the initial forward wheel, but it is advantageous to put the drum onthe forward wheel, rather 'mit the relatively large thrust opposite toturbine, 0r requlre expensive reconstruction of the casing. The pipe 17can be connected at any point in the drum stages where the desiredpressure is found, depending upon the particular installation.

Various modifications and changes may be made in the construction hereinillustrated without departing from the scope of the appended claims.

aving thus described my invention, what I declare as new and desire tosecure by Letters Patent of the United States is 1. In a steam turbinedrive for a ship, the combination with a propeller shaft havinga'driving thrust in one direction of a series of steam turbine stagesfor driving said shaft and mounted on a drum having an axial thrustopposite to the driving thrust of said propeller shaft, a plurality ofturbine wheel stages driving said shaft, said drum stages beingsubstantially greater in number than said wheel stages so as toincreasethe efficiency of the drive, and means for exertinga counterthrust to counterbalance the excess of said drum thrust and pernumber ofdrum stages, comprising means for reducing the rearward pressure on oneof said wheels.

2. In a steam turbine drive for a ship, the combination with a propellershaft having a driving'thrustin one direction of a series of 100 steamturbine stages for driving said shaft and mounted on a drum having anaxial the driving thrust of said propeller shaft, a plurality of turbinewheel stages driving said shaft, said drum stages being substantiallygreater in number than said wheel stages so as to increase the efli-'ciency of the drive, and means for exerting a counter thrust tocounterbalance the ex cess of said drum thrust and permit the relativelylarge number of drum stages com-. prising a dummy drum on one of saidwheels having an annular steam tight packing engagement with the turbinecasing and its interior pressure reduced to increase the pressure on itshead in the direction of said propeller thrust.

3. In a steam turbine drive for a ship, the

combination with a propeller shaft having imp; i B

. permit the re1ative1y1ar e number of drum the pressure on its head inthe direction of stages comprising.v a we for one of said saidpnopellerthrust. q turbine Wheels having a passage time Intestimony'whereof I aflix my ign'ature through to equalize the pressure on eachside in presence f w Witnesses- I i of said web and a dummy drum. on oneof r JOHN F. METTEN.

said Wheels having an annular steam tight Witnesses:

packing engagement with the turbine easing JOHN H. McMAsTnR, and itsinterior pressure reduced. to Increase i Isaac H. WRIGHT,

Copies of this patent may be obtained to: five gents each, byfaddressing the f'coniminioner or intents,-

Wilmington, D. 0. x

